Q. I noticed that many different types of fruit trees lose a lot of fruit around this time of the year. What causes this? Michelle, San Luis Obispo
A. During this marvelous spring season you have watched excitedly as your fruit trees have flowered spectacularly and youve seen many fruit begin to form. Then, one day you are horrified to see that a large number of good-sized fruit have fallen to the ground. Dont panic, this is normal for fruit trees. In fact, it even has a name, June drop, so-called because this usually occurs in early June.
A fruit tree is only capable of supporting a certain amount of fruit. If every one of those flowers were to produce a fruit, the tree would literally collapse under the weight. Too large of a crop will strain the trees resources and result in smaller fruit of lesser quality. June drop is a natural phenomenon, a self-regulated thinning process that keeps trees from bearing too large of a crop.
Actually, there was an earlier wave of fruit drop that you probably didnt notice. Some fruit begin to drop soon after flowering, primarily small fruit that were poorly pollinated. June drop is more obvious than this earlier drop because the fruit are larger and more noticeable.
Fruit trees set fruit in order to produce seed for reproduction. This reproductive growth phase begins with the creation of flowers, and as insurance to offset losses from weather or other cultural factors, fruit trees always generate more flowers than they need for a full crop of seeds.
In spite of this natural phenomenon, many fruit trees dont thin themselves enough and will still need some hand-thinning assistance from us. If you cant bring yourself to remove the excess fruit, your harvested fruit will be smaller and of poorer quality.
By the way, its called June drop, but it may occur in May, June or July. For more information about fruit trees, visit The California Backyard Orchard: http://homeorchard.ucdavis.edu.